Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: Rimmel on April 11, 2018, 07:52:22 AM

Title: Homing switches - optical?
Post by: Rimmel on April 11, 2018, 07:52:22 AM
I have been using Mach3 a while now and realised that the mechanical homing switches are terrible. I would liike to swap them to a more accurate version, I hear optical is a good option, although they do require and extra wire and perhaps a little circuit?

Has anyone got any insight on this? Does anyone make Opto units complete and ready to go?

thanks
Rim
Title: Re: Homing switches - optical?
Post by: Davek0974 on April 11, 2018, 09:22:21 AM
I would go for inductive proximity sensors myself, pretty accurate if setup right and not so prone to dust/swarf etc as optical
Title: Re: Homing switches - optical?
Post by: joeaverage on April 11, 2018, 09:34:44 AM
Hi,
I use roller plunger microswitches for homing and get repeat accuracy of 0.02mm.

http://nz.element14.com/honeywell/bzc-2rq18-a2/switch-basic-top-roller-plunger/dp/1525198 (http://nz.element14.com/honeywell/bzc-2rq18-a2/switch-basic-top-roller-plunger/dp/1525198)

What kind of mechanical switches are you using?

Craig
Title: Re: Homing switches - optical?
Post by: Rimmel on April 11, 2018, 09:43:31 AM
Hi,
I use roller plunger microswitches for homing and get repeat accuracy of 0.02mm.

http://nz.element14.com/honeywell/bzc-2rq18-a2/switch-basic-top-roller-plunger/dp/1525198 (http://nz.element14.com/honeywell/bzc-2rq18-a2/switch-basic-top-roller-plunger/dp/1525198)

What kind of mechanical switches are you using?

Craig

I am using roller plunger switches - tried loads and not getting that sort of accuracy.

Rim
Title: Re: Homing switches - optical?
Post by: Rimmel on April 11, 2018, 09:44:14 AM
I would go for inductive proximity sensors myself, pretty accurate if setup right and not so prone to dust/swarf etc as optical

Sounds good - got a link to any?

thanks
Title: Re: Homing switches - optical?
Post by: Davek0974 on April 11, 2018, 09:47:21 AM
Plenty options - very common

https://www.ebay.co.uk/itm/New-LJ12A3-4-Z-BX-Inductive-Proximity-Sensor-Detection-Switch-NPN-DC6-36V-4mm/122206045078?hash=item1c740c4396:g:hJkAAOSwdzVXuulS

for example.

need to choose NPN, PNP etc as needed.

Is this on a stepper drive machine?
Title: Re: Homing switches - optical?
Post by: LerninCNC on April 11, 2018, 10:44:34 AM
Not sure where you are located but Automation Direct (USA) sells High Precision Touch and Tool Setter limit switches.  They claim 0.5 micron (µm) repeat accuracy, no movement differential, no temperature drift, and dustproof / water-resistant (IP67).  Not cheap though, $116 USD.  Hope this is helpful.
Title: Re: Homing switches - optical?
Post by: Rimmel on April 11, 2018, 11:02:03 AM
Plenty options - very common

https://www.ebay.co.uk/itm/New-LJ12A3-4-Z-BX-Inductive-Proximity-Sensor-Detection-Switch-NPN-DC6-36V-4mm/122206045078?hash=item1c740c4396:g:hJkAAOSwdzVXuulS

for example.

need to choose NPN, PNP etc as needed.

Is this on a stepper drive machine?

The problem being that most mach 3 BoB's are 5v for the limit switches and all the proximity switches start at 6v.

It is a stepper at present.

thanks
Title: Re: Homing switches - optical?
Post by: Rimmel on April 20, 2018, 07:38:09 AM
For anyone interested I found the same Inductive Prioximity switches in 5v avaiable here: https://www.ebay.co.uk/itm/M12-LJ12A3-4-Z-BX-5V-DC-5V-NPN-NO-300mA-Inductive-Proximity-Sensor-Switch-4mm/352165249518?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 (https://www.ebay.co.uk/itm/M12-LJ12A3-4-Z-BX-5V-DC-5V-NPN-NO-300mA-Inductive-Proximity-Sensor-Switch-4mm/352165249518?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649)

Ebay number 352165249518 if the link does not work: Just past number into ebay search box and press enter.

Ordered from China on 13th April and arrived on the 19th April (I am in the UK - land of the liberal idiot) - they work brilliantly and no faffing about with resistors and/or extra power supplies.

Result!
Rim
Title: Re: Homing switches - optical?
Post by: Davek0974 on April 20, 2018, 07:54:38 AM
Nice :)